Out of respect for costar SofiaVergara and her fiance, NickLoeb, Modern Family's Jesse TylerFerguson kept his engagement to Justin Mikita under wraps for nearly three months!

On September 19, Ferguson, 36, revealed he had popped the question in a video for Tie The Knot, an organization he and Mikita, 27, launched to support marriage equality. Ferguson shared new details about their engagement during an interview with Access Hollywood at the 64th Emmy Awards in L.A. September 23.

"It happened in Mexico, ironically a few days before Sofia got engaged," Ferguson recalled. The future spouses -- joined by 88 additional guests -- were visiting the country to help Vergara celebrate her 40th birthday in mid-July.

"I told Sofia the day before she got engaged. Very quietly, I said, 'Justin and I got engaged, but we don't want to tell a lot of people and we don't want to upstage you on your big birthday weekend' -- and then the next day she gets engaged on a Tulum ruin!" Ferguson laughed. "So, she has upstaged us."

Ferguson and Mikita, who first stepped out together in January 2011, have yet to set a date for their own wedding. "We don't know yet," said Ferguson, who lost the award for Outstanding Supporting Actor in a Comedy Series to his Modern Family costar Eric Stonestreet, 41. "Don't hold your breath."